Well I finally found out what was causing my carburetor to leak. It would drip whether or not the tank valve was turned off.

I took the carb apart and cleaned it up, and noticed it had the neoprene needle valve, so I thought maybe the new gas was causing a problem so I ordered the original type needle and seat and a set of gaskets. Today I took it apart and replaced the needle and seat and gaskets. Put the carb on the car and it still dripped.

The design of both Kingston and Holley were poor! What I found was the brass insert which holds the bowl to the carburetor was leaking. About 1/4 turn fixed the leak. I don't know why both those carbs had that type of fastener to the bowl. It would have cost a few cents more to have a solid bowl and screws to hold it to the body at the top of the bowl. Well anyway, what I found was that on the bench I thought the insert was tight and didn't want to strip the brass. But after the carb was mounted to the manifold, I had more leverage and it felt very loose. When I tightened it the leak stopped. So much for now. I hope that's all that was leaking. Norm

Well! I just checked it again and there was a small seepage. This time I used fast drying hard setting permatex. I will let it set overnight with the gas turned off. I sure hope I got everything inside set correctly so it doesn't need to come apart soon! Norm

I recall hearing a story about an engineer bringing a prototype carb to Ford, that had a number of screws holding it together. His comment that there was too many screws, redesign it! You have to remember that screws were not as cheap as they are now, and that they were a part that could be damaged or come loose. The simplicity of the Carbs used on the T are amazing. Best Gus

The story is from the development of the Model A. To get the HP that Henry wanted out of the motor (40HP) they needed to change from a Holly carb to a Zenith. (Henry was good friends with John Holly and there was concern he would balk) The Zenith had something like 16 screws holding it together. Henry took one look and said "To many...get rid of the screws" They went back to Zenith and they redesigned with 2 screws. Henry looked and said "Still to many" That's why the carb had one center bolt holding it together.

It still leaks. The bowl doesn't leak, but seems something inside. The gas comes out the air intake around the choke. I replaced the needle and seat and set the float level. Is there anything internal to a Holley which could cause a leak other than the needle and seat?

It doesn't leak enough to cause any problem with the way the engine runs, just when parked. When I run out of gas, I want to use some timesaver on the shut off valve so at least I can turn it off and it will not leak.

P.S. The zenith carburetor has one bolt, but it doesn't go through the bowl. Norm Norm

It can leak around the threads of the seat for the needle.I aint sure it is worth a hoot but the last time I had 1 apart I put some of the yellow teflon tape around the threads of the needle seat and the bowl bolt.

I have an NH Holley carb and it appears that I can screw the bowl bolt in far enough to block the hole that goes thru the treaded part of the bolt. Wouldn't that block the flow of the gas? From just eyeballing it I am guessing the gas gets sucked straight up from the bottom of the bowl and then heads out to the intake manifold. Your thoughts?